Cartoons can dream up any creature they want, and some of their best inventions come from other planets entirely. The best alien cartoon characters run the range from world-conquering invaders to fuzzy little sweethearts who just want a hug.
This is a ranking by how iconic each one is, so a Looney Tunes legend edges out a cult-favorite blob.
A quick note on the guest list: everyone here is an actual non-Earth being.
A couple are loose fits, and one is more interdimensional than extraterrestrial, so I have flagged those as we go. Ranked from deep cut to household name, here they are.
The Best Alien Cartoon Characters, Ranked
ALF (ALF: The Animated Series)
ALF crash-landed from the planet Melmac and moved in with a suburban family, running on sarcasm and a not-entirely-joking appetite for the family cat. He was a live-action puppet star first, but his Saturday-morning cartoon spun his Melmac past into full animated adventures.
- Appears in: ALF: The Animated Series
- Home planet: Melmac
- Known for: nonstop wisecracks and eyeing the family cat
Wander (Wander Over Yonder)
Wander is a fuzzy orange optimist who roams the galaxy spreading kindness whether anyone asked for it or not. Backed by his loyal steed Sylvia, he tends to defeat villains just by being relentlessly, disarmingly nice.
- Appears in: Wander Over Yonder
- Home planet: unknown, a wandering alien nomad
- Known for: helping everyone, including the villains trying to conquer the galaxy
Mooncake (Final Space)
Mooncake looks like an adorable green blob with one big eye, right up until it fires a planet-destroying laser. This tiny cosmic creature is one of the most powerful beings in Final Space and, somehow, also the cutest.
- Appears in: Final Space
- Origin: a rare cosmic organism, a living planet-destroyer
- Known for: devastating energy blasts paired with adorable chirping
Star Butterfly (Star vs. the Forces of Evil)
Star Butterfly is a magical princess sent to Earth as a foreign-exchange student, though “foreign” undersells it: she hails from the entirely separate dimension of Mewni. She counts as an alien in the loosest sense, a non-Earth royal armed with a wand and zero impulse control.
- Appears in: Star vs. the Forces of Evil
- Home world: Mewni, another dimension rather than deep space
- Known for: chaotic wand magic and boundless enthusiasm
Zim (Invader Zim)
Zim is a pint-sized Irken invader sent to conquer Earth, mostly because his own leaders wanted him as far away as possible. He is loud, incompetent, and hilarious, forever scheming with his malfunctioning robot GIR. For the record, only Zim is an alien here, since GIR is a robot and Gaz is a human classmate.
- Appears in: Invader Zim
- Home planet: Irk, home of the Irkens
- Known for: doomed plans to conquer Earth with GIR at his side
The Crystal Gems (Steven Universe)
The Crystal Gems are alien warriors made of living gemstones, projecting bodies of pure light from the stones at their core. Garnet, Amethyst, and Pearl rebelled against their own alien Homeworld to protect Earth, raising the half-human Steven along the way.
- Appears in: Steven Universe
- Home planet: Homeworld, which they defected from
- Known for: light-based bodies, fusion, and fierce loyalty to Earth
The Great Gazoo (The Flintstones)
The Great Gazoo is a tiny floating alien banished to prehistoric Earth as punishment for inventing a doomsday weapon. Visible only to Fred and Barney, he reluctantly grants wishes that always backfire while calling everyone “dum-dum.”
- Appears in: The Flintstones
- Home planet: Zetox
- Known for: floating, condescending, and backfiring wishes
Kang and Kodos (The Simpsons)
Kang and Kodos are the drooling, tentacled aliens who turn up every Simpsons Treehouse of Horror to menace Springfield. Hailing from Rigel VII, the cackling duo has tried everything from abduction to rigging a presidential election, always with maximum evil laughter.
- Appears in: The Simpsons, in the Treehouse of Horror specials
- Home planet: Rigel VII
- Known for: tentacles, drool, and villainous cackling
Starfire (Teen Titans)
Starfire is a warrior princess from the planet Tamaran who turns her emotions into raw energy, firing starbolts when angry and flying when joyful. Her wide-eyed optimism and very literal read on Earth slang make her the warm heart of the Teen Titans.
- Appears in: Teen Titans
- Home planet: Tamaran
- Known for: emotion-powered flight and glowing green starbolts
Roger (American Dad!)
Roger is the crash-landed grey alien who lives in the Smith family attic and contributes nothing but chaos. A master of disguise with hundreds of personas, he is petty, flamboyant, and easily the most unhinged member of this adult-animation household.
- Appears in: American Dad!
- Home planet: unknown, a grey alien hiding out with the Smiths
- Known for: a bottomless closet of wigs, personas, and schemes
The Little Green Men (Toy Story)
The Little Green Men are the three-eyed squeeze toys who live in a Pizza Planet claw machine and worship “The Claw” as their almighty master. They are toys rather than true aliens, but their gently unhinged devotion made them one of Pixar’s most quotable creations.
- Appears in: the Toy Story franchise
- Home: the Pizza Planet claw machine, since they are alien toys
- Known for: chanting in eerie unison and revering The Claw
Stitch (Lilo and Stitch)
Stitch, also known as Experiment 626, is a genetically engineered blue alien built to destroy, who instead learns about family on a Hawaiian beach in Lilo and Stitch. Fast, strong, and nearly indestructible, he is chaos incarnate until Lilo teaches him what “ohana” means.
- Appears in: Lilo and Stitch
- Origin: an illegal genetic experiment, Experiment 626, from deep space
- Known for: super strength, four arms, and a soft heart under the chaos
Marvin the Martian (Looney Tunes)
Marvin the Martian is the original cartoon alien and still the gold standard. Tiny, soft-spoken, and unfailingly polite, he has spent decades calmly trying to blow up the Earth because it blocks his view of Venus, forever foiled by Bugs Bunny.
- Appears in: Looney Tunes
- Home planet: Mars
- Known for: his Roman helmet, his tiny voice, and his missing kaboom
My Quick Cartoon-Alien Takeaway
Most lovable: Stitch
Best villains: Kang and Kodos
Loosest fit: Star Butterfly
Alien Cartoon Characters FAQ
Who is the most famous alien cartoon character? Marvin the Martian and Stitch are the usual answers, with Roger from American Dad! and Starfire from Teen Titans close behind.
Are the Toy Story aliens real aliens? Not quite. The Little Green Men are alien-themed squeeze toys rather than actual extraterrestrials, but they are far too iconic to leave off a list like this.
Which cartoon aliens are best for young kids? Stitch, the Little Green Men, Wander, and Starfire are all friendly, upbeat picks with very little to worry about.
Which cartoon alien is the most powerful? Mooncake, with its planet-destroying blasts, and the Crystal Gems rank near the top for raw power despite their small or friendly appearances.
From Mars to Melmac to Mewni, these alien cartoon characters prove the galaxy is animation’s favorite playground. So who is your favorite cartoon alien? Beam your pick down in the comments.